The dresses, all in the signature 1980s look — padded shoulders, puffed sleeves, crushed velvet — are snapshots in the princess's glamorous, jet-setting life.

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One Catherine Walker long-sleeved gown in sea-green sequins was worn to a grand Vienna theater; a burgundy velvet gown with a plunging back, by the same designer, was paired with the Spencer tiara on a visit to Canberra, Australia; and a black, beaded velvet gown, also by Walker, was worn in 1997 for a Vanity Fair photo shoot by Mario Testino.

But the most celebrated item was the Edelstein gown with off-the-shoulder straps, which Diana chose for her and Prince Charles' first joint visit to the White House.

The princess paired it with a stunning sapphire and pearl choker for a state dinner given by President Ronald Reagan, where, after dinner, she and Travolta twirled on the White House dance floor to tunes from the actor's hit movie "Saturday Night Fever."

Travolta said afterward: "She turned around and she did that look that she did so, so beautifully and I asked if she would care to dance and she said she'd love to."

The gown, which Diana wore on at least four other occasions, is expected to sell for up to 300,000 pounds.

The other dresses, valued from 30,000 pounds to 120,000 pounds, include a pale pink A-line gown and bolero set, both richly embroidered in crystals and sequins; a one-shouldered cream and floral-embroidered number; and a white chiffon cocktail dress with a draped skirt.

Diana decided to sell dozens of her dresses at a New York charity auction at the suggestion of her son, Prince William, in 1997 — three months before she died in a Paris car crash. Florida-based socialite Maureen Dunkel bought about a dozen of the dresses — including the ten to be sold next month — and put them up for auction in Canada in 2011, but the prices were set too high and many dresses didn't sell.

Kerry Taylor Auctions declined to disclose the identity of the sellers for the dresses in the upcoming auction. Taylor said only that this time the prices are "realistic" and buyers have already shown interest.